Economical boosted high speed data cable

ABSTRACT

A high speed video cable carries signals according to the High-Definition Multimedia Interface (HDMI), and includes a raw cable and a boost device. Each of four high speed video signals is carried on the inner conductors of a pair of coaxial lines in the raw cable. Lower speed signals are carried on the galvanically or capacitively coupled shields of a pair of coaxial lines, thus permitting fourteen HDMI signals to be carried in a cable comprising only eight coaxial lines, resulting in a simpler and lower cost production and assembly of the cable.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is Continuation-in-Part of the U.S. application Ser.No. 12/805,101 filed on Jul. 13, 2010, the entire contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the construction of boosted high speeddata cables, which carry high speed signal lines.

BACKGROUND OF THE INVENTION

The distribution of television signals has increasingly become based ondigital methods and digitally encoded forms of video and audio signals.At the same time, higher resolution (high definition TV) has becomeavailable in the market place, commensurate with larger and higherdefinition displays. To meet the requirement of interconnecting suchhigh definition displays with digital signal sources such as DigitalVersatile Disc (DVD) players and receivers/decoders for digitalsatellite and digital cable distribution of video material, a digitalinterface standard has evolved, known as the High-Definition MultimediaInterface (HDMI). A detailed specification for HDMI can be obtained fromthe “hdmi.org” website. The HDMI specification currently available andused in this application is HDMI specification version 1.4a dated Mar.4, 2010, which is incorporated herein by reference.

HDMI cables of various construction may be used for transmitting highspeed digital signals from digital signal sources, including, but notlimited to, the examples listed above, to digital displays or otherequipment designed to receive signals according to the HDMIspecification.

A HDMI cable carries not only four high speed differential signals whichare shielded, but also a number of lower speed signals, power andground, the whole being further shielded by an outer braid. Theresulting complex cable configuration with numerous wires, some of whichare individually shielded, is expensive to manufacture and terminate.

Another standard for connecting video source to a video sink, ispublished as the DisplayPort standard by the Video Electronics StandardsAssociation (VESA). The latest DisplayPort specification used in thisapplication is DisplayPort v1.2, dated Jan. 5, 2010 which is submittedin the Information Disclosure Statement for this application. TheDisplayPort standard specifies a high speed data cable that is intendedprimarily to be used between a computer and its display monitor or ahome-theater system. A cable meeting the DisplayPort standard is verysimilar to an HDMI cable, the main difference being in the respectivephysical connectors.

Therefore there is a need in the industry for developing an improved andeasier to manufacture high speed cable, which would avoid or mitigatethe shortcomings of the prior art and provides significant economies atthe same time.

SUMMARY OF THE INVENTION

Therefore there is an object of the invention to provide an improvedboosted high speed data cable using a reduced number of wire elements,which would be more economical and have superior properties overexisting prior art cables.

According to one aspect of the invention, there is provided a cable forcarrying a high speed differential digital data signals and one or moreauxiliary signals between a source device and a sink device according toa cable specification, the cable comprising:

-   -   a raw cable, comprising a split dual shielded cable element,        comprising two shielded conductors, each of said two shielded        conductors being enclosed in an individual shield;    -   individual shields of the shielded conductors are designated for        carrying respective auxiliary signals; and    -   the shielded conductors of the split dual shielded cable element        are designated for carrying the high speed differential digital        data signal.

The cable further comprises a coupling capacitor for capacitivelycoupling the individual shields of the split dual shielded cableelement. Conveniently, capacitance of the coupling capacitor is chosento be low enough not to cause cross talk between low speed auxiliarysignals, but high enough to preserve transmission characteristics of thedual shielded cable element with respect of the high speed differentialsignal.

The cable may further comprise a boost device for boosting the highspeed differential digital data signals.

In the cable described above, the raw cable further comprises a dualshielded cable element, comprising two shielded conductors and a commonshield;

wherein:

the two shielded conductors of the dual shielded cable elements aredesignated for carrying a respective high speed differential digitaldata signal; and

the common shield of the shielded conductors is designated for carryingan additional auxiliary signals.

The cable further comprises a first circuit carrier for connecting theraw cable to the source device, and a second circuit carrier forconnecting the raw cable to the sink device.

The first circuit carrier comprises:

-   -   terminals for connecting the high speed differential digital        data signal from the source device to respective shielded        conductors of the split dual shielded cable element; and    -   terminals for connecting respective auxiliary signals from the        source device to the individual shields respectively; and        the second circuit carrier comprises:    -   terminals for connecting the high speed differential digital        data signals from respective shielded conductors of the split        dual shielded cable element to the sink device; and    -   terminals for connecting respective auxiliary signals from the        individual shields to the sink device.

In an embodiment of the invention, capacitance of the coupling capacitoris about 1 nF.

The cable of the embodiments of the invention has been designed tosatisfy the cable specification, which is a High-Definition MultimediaInterface (HDMI) standard.

Conveniently, the individual shields of the split dual shielded cableelement are designated for carrying Power and Ground auxiliary signals.Alternatively, the individual shields of the split dual shielded cableelement may be designated for carrying a Hot Plug Detect (HPD) auxiliarysignal and CEC (Consumer Electronics Control) auxiliary signal.

In an embodiment of the invention, the raw cable comprises only twosplit dual shielded cable elements, and two dual shielded cableelements, each dual shielded element comprising two shielded conductorsand a common shield.

Alternatively, the cable may be designed to satisfy the cablespecification, which is a DisplayPort standard.

In an embodiment of the invention, said split dual shielded cableelement is a split dual coaxial element, comprising two coaxial lineswhose shields are capacitively coupled to one another, and each coaxialline enclosing one shielded conductor; and the dual shielded cableelement is a dual coaxial element, comprising two coaxial lines whoseshields are joined, and said shields of each coaxial line enclosing arespective shielded conductor.

According to yet another aspect of the invention, there is provided amethod for transmitting a high speed differential digital data signaland one or more auxiliary signals between a source device and a sinkdevice according to a cable specification over a cable extending betweenthe source device and the sink device, the method comprising:

-   -   carrying the high speed differential digital data signal over        the cable in two shielded conductors of a split shielded cable        element, each of the two shielded conductors having an        individual shield; and    -   carrying said one or more auxiliary signals on respective        individual shields of the shielded conductors.

The method further comprises a step of capacitively coupling theindividual shields of the split dual shielded cable element.

The method further comprises carrying yet another auxiliary signal on acommon shield of a dual shielded cable element comprising two shieldedconductors and the common shield.

In the method described above, the carrying is performed according tothe cable specification, which is a High Definition Multimedia Interface(HDMI) standard or a DisplayPort standard.

Thus, a lower cost boosted high speed data cable and a method oftransmitting digital signals over the cable have been provided.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example,with reference to the accompanying drawings in which:

FIG. 1A shows a simplified boosted cable 10 to illustrate the principleof transmitting a single-ended signal and a differential signal over ashielded cable comprising a dual shielded cable element 12, which is aShielded Twisted Pair (STP), and a boost circuit 20;

FIG. 1B shows a dual coaxial element 12B that may be used instead of thedual shielded cable element 12 of FIG. 1A;

FIG. 2 shows a configuration 100 of a generic Boosted Digital VideoCable 102.j which may be any of a number of types according toembodiments of the invention, interconnecting a Video Source Device (Tx)104 and a Video Sink Device (Rx) 106;

FIG. 3 shows a Basic Coax HDMI Cable 102.1 based on coax technologyaccording to a first embodiment of the invention;

FIG. 4 shows a Basic STP HDMI Cable 102.2 based on Shielded Twisted Pair(STP) technology according to a second embodiment of the invention;

FIG. 5 shows a HEAC-Capable Coax HDMI Cable 102.3 based on coaxtechnology according to a third embodiment of the invention;

FIG. 6 shows a HEAC-Capable STP HDMI Cable 102.4 based on ShieldedTwisted Pair (STP) technology according to a fourth embodiment of theinvention;

FIG. 7 shows a Coax DisplayPort Cable 102.5 based on coax technologyaccording to a fifth embodiment of the invention;

FIG. 8 shows a STP DisplayPort Cable 102.6 based on Shielded TwistedPair (STP) technology according to a sixth embodiment of the invention;

FIG. 9 shows a three coax line cross sections, to illustrate acomparison between exemplary design choices, including a standard coax902; a reduced-outer-diameter coax 904; and an increased-core-diametercoax 906;

FIG. 10 shows a Low-Impedance Coax HDMI Cable 102.10 which is identicalto the Basic Coax HDMI Cable 102.1 of FIG. 1 except for a Low-ImpedanceInput Paddle Board 114.10 which replaces the first Input Paddle Board114.1;

FIG. 11 shows a High-Impedance (High Z0) Coax HDMI Cable 102.11 which isidentical to the Basic Coax HDMI Cable 102.1 of FIG. 3 except for aHigh-Impedance Input Paddle Board 114.11 replacing the first InputPaddle Board 114.1;

FIG. 12A shows a basic configuration 1200 of a split dual shielded cableelement 1202 including two coax lines 1204 and 1206, analogous to thedual coaxial element 12B of FIG. 1 b for carrying the differentialsignal “D”;

FIG. 12B illustrates a First 8-Coax HDMI Cable 102.12 including a First8-Coax Input Paddle Board 114.12, a First 8-Coax Raw Cable 108.12, and aFirst 8-Coax Output Paddle Board 116.12, as well as the Input and OutputConnection Fields 212 and 214;

FIG. 13A illustrates an expanded generic diagram 1300 of the genericBoosted Digital Video Cable 102.j of FIG. 2;

FIG. 13B illustrates a general diagram of a Second 8-Coax HDMI Cable102.13, which includes a Second 8-Coax Input Paddle Board 114.13, aSecond 8-Coax Raw Cable 108.13, and a Second 8-Coax Output Paddle Board116.13;

FIG. 14 shows a detailed diagram of the Second 8-Coax HDMI Cable 102.13of FIG. 13B, including detailed diagrams of the Second 8-Coax InputPaddle Board 114.13, the Second 8-Coax Raw Cable 108.13, and the Second8-Coax Output Paddle Board 116.13;

FIG. 15 shows a configuration 1500 of a generic Unboosted Digital VideoCable 1502.k which may be any of a number of types described in thefollowing figures, according to embodiments of the invention,interconnecting the Video Source Device (Tx) 104 and the Video SinkDevice (Rx) 106;

FIG. 16 shows a Basic Unboosted Coax HDMI Cable 1502.1 based on coaxtechnology according to an embodiment of the invention, including theInput Connection Field 212, the first Input Paddle Board 114.1, thefirst Raw Cable 108.1, the Output Connection Field 214, as well as afirst Unboosted Output Paddle Board 1504.1;

FIG. 17 shows a Basic Unboosted STP HDMI Cable 1502.2 based on ShieldedTwisted Pair (STP) technology according to an embodiment of theinvention, including the Input Connection Field 212, the second InputPaddle Board 114.2, the second Raw Cable 108.2, the Output ConnectionField 214, as well as a second Unboosted Output Paddle Board 1504.2;

FIG. 18 shows an Unboosted HEAC-Capable Coax HDMI Cable 1502.3 based oncoax technology according to an embodiment of the invention, includingthe HEAC-capable Input Connection Field 412, the third Input PaddleBoard 114.3, the third Raw Cable 108.3, the HEAC-capable OutputConnection Field 414, as well as a third Unboosted Output Paddle Board1504.3;

FIG. 19 shows an Unboosted HEAC-Capable STP HDMI Cable 1502.4 based onShielded Twisted Pair (STP) technology according to an embodiment of theinvention, including the HEAC-capable Input Connection Field 212, thefourth Input Paddle Board 114.4, the fourth Raw Cable 108.4, theHEAC-capable Output Connection Field 214, as well as a fourth UnboostedOutput Paddle Board 1504.4;

FIG. 20 shows an Unboosted Coax DisplayPort Cable 1502.5 based on coaxtechnology according to an embodiment of the invention, including theDisplayPort Input Connection Field 612, the fifth Input Paddle Board114.5, the fifth Raw Cable 108.5, the DisplayPort Output ConnectionField 614, as well as a fifth Unboosted Output Paddle Board 1504.5;

FIG. 21 shows an Unboosted STP DisplayPort Cable 1502.6 based onShielded Twisted Pair (STP) technology according to an embodiment of theinvention, including the DisplayPort Input Connection Field 612, thesixth Input Paddle Board 114.6, the sixth Raw Cable 108.1, theDisplayPort Output Connection Field 614, as well as a sixth UnboostedOutput Paddle Board 1504.6;

FIG. 22 shows an Unboosted Low-Impedance Coax HDMI Cable 1502.10 whichis identical to the Basic Unboosted Coax HDMI Cable 1502.1 of FIG. 16except for the Low-Impedance Input Paddle Board 114.10 instead of thefirst Input Paddle Board 114.1, and includes the Input Connection Field212, the first Raw Cable 108.1, the Output Connection Field 214, as wellas a Low-Impedance Unboosted Output Paddle Board 1504.10;

FIG. 23 shows an Unboosted High-Impedance Coax HDMI Cable 1502.11 whichis identical to the Basic Unboosted Coax HDMI Cable 1502.1 of FIG. 16except for the High-Impedance Input Paddle Board 114.11 instead of thefirst Input Paddle Board 114.1, and includes the Input Connection Field212, the first Raw Cable 108.1, the Output Connection Field 214, as wellas a High-Impedance Unboosted Output Paddle Board 1504.11; and

FIG. 24 shows an Unboosted Low-Impedance 8-Coax HDMI Cable 1502.13,including the Input Connection Field 212, the Second 8-Coax Input PaddleBoard 114.13, the Second 8-Coax Raw Cable 108.13, the Output ConnectionField 214, as well as a Low-Impedance Unboosted Output Paddle Board1504.13.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

Embodiments of the present invention describe a boosted high speed cablecomprising shielded high speed signal lines and carrying other signalsof lower speed as well as power and ground, in which the shields of theshielded high speed signal lines are used in carrying the lower speedsignals and power and ground.

The inherent characteristics and manufacturing imperfections ofhigh-speed differential signaling cables such as may be used to carryHDMI signals have an adverse effect on the high-speed signals carried bythe cable. To mitigate these effects, various boosted high speed datacables have been proposed by the industry. For example, in thepreviously filed US application of the same assignee, Ser. No.11/826,713 filed on Jul. 18, 2007, a boost device is embedded in thecable, the entire contents of the patent application being incorporatedherein by reference.

The inventors have discovered that the boost device may not only be usedto equalize and boost the signal, as described in the U.S. applicationSer. No. 11/826,713 cited above, but may also be used to advantage inother ways, specifically to allow the individual shields of thedifferential high speed signals to be used for carrying other signals.

In a cable of the prior art, the shields are all tied to ground in aneffort to reduce electro-magnetic interference (EMI). In a cableaccording to any of the embodiments of the invention, EMI shielding isstill provided, but instead of tying the shields of the high-speed HDMIsignals to ground, the lower speed signals as well as power and ground,are sent over the shields.

FIG. 1A shows a simplified boosted cable 10 to illustrate the principleof transmitting a single-ended signal and a differential signal over ashielded cable. The simplified boosted cable 10 comprises a dualshielded cable element 12 which is a Shielded Twisted Pair (STP)including a single shield 14 enclosing first and second signal wires(two shielded conductors) 16 and 18 respectively, and a boost circuit 20having inputs i+ and i− and outputs o+ and o−. The inputs i+ and i− ofthe boost circuit 20 are a differential input pair and the outputs o+and o− of the boost circuit 20 are a differential output pair.

The simplified boosted cable 10 receives a single-ended signal “A” and adifferential signal “D” comprising polarities D+i and D−i at the inputof the simplified boosted cable 10, and is designed to deliver thesesignals substantially undistorted at its output. The boost circuit 20includes an equalizer circuit (EQ) and a differential amplifier (Amp)for equalizing and boosting the differential signal “D”.

The signal wires 16 and 18 carry the differential signal “D”, comprisingpolarities D+i and D−i respectively from the input of the simplifiedboosted cable 10 through the dual shielded cable element 12 to theinputs i+ and i− of the boost circuit 20. The outputs o+ and o− of theboost circuit 20 deliver a processed differential signal comprisingpolarities D+o and D−o to the output of the simplified boosted cable 10,which represent the differential signal “D”.

The single shield 14 carries a single-ended signal “A” directly from theinput of the simplified boosted cable 10 to its output.

The processing functions of the boost circuit 20 include: receiving thedifferential input signal; removing any common mode component of thedifferential input signal; equalizing the signal to compensate forsignal impairments introduced by the dual shielded cable element 12; andoutputting a boosted version of the equalized differential signal “D”.

To summarize, the differential signal is a high-speed data signal “D”,which may benefit from equalization and boosting while the single-endedsignal “A” may be a ground signal, a power supply signal, or any lowspeed signal which does not require equalization or boosting.

Along the length of the STP raw cable 12, a small fraction of thesingle-ended signal “A” is unavoidably coupled as undesirable noisethrough distributed capacitances 22 and 24 into the signal wires 16 and18 respectively, thus affecting the differential signal “D”. Given that,by the construction of the dual shielded cable element 12, thecapacitances 22 and 24 are essentially equal, the polarities D+i and D−irespectively are equally affected, and the coupled noise manifestsitself as common mode noise.

At the receiving end of the dual shielded cable element 12, the boostcircuit 20 receiving the differential signal “D”, provides sufficientcommon-mode rejection such that the common mode noise is not convertedinto a differential signal. The ouputs o+ and o− of the boost circuit20, that produces a boosted signal, is then a clean differential signalwhich is delivered at the output of the simplified boosted cable 10.

Alternatively, as shown in FIG. 1B, a dual coaxial element 12B may beused instead of the dual shielded cable element 12. The dual coaxialelement 12B is comprised of two coaxial lines 26 and 28 forming a coaxpair 30 whose outer conductors (shields) are joined together, the joinedshields providing the connection for the single-ended signal “A”. Thecoaxial line 26 carries the polarity D+i of the differential signal “D”on its inner conductor 32, while the coaxial line 28 carries thepolarity D−i of the differential signal “D” on its inner conductor 34.Coupling between the single-ended signal “A” and the inner conductors 32and 34 which are also referred to as shielded conductors, throughdistributed capacitances 36 and 38 respectively is analogous to the caseof the dual shielded cable element 12, resulting in common mode noiseonly which is rejected by the boost circuit 20.

In the following figures, various boosted HDMI cable configurations areshown which are embodiments of the invention that are based on the cableelements described in FIGS. 1A and 1B.

FIG. 2 shows a configuration 100 of a generic Boosted Digital VideoCable 102.j which may be any of a number of types to be described below,connecting a Video Source Device (Tx) 104 to a Video Sink Device (Rx)106. The Boosted Digital Video Cable 102.j comprises a Raw Cable 108.j,and Input and Output Connectors 110 and 112 respectively.

The Input Connector 110 connects the Raw Cable 108.j to the Video SourceDevice (Tx) 104, and comprises an Input Paddle Board 114.j for providingconnectivity between signals from the Video Source Device (Tx) 104 andfacilities (wires, shields) of the Raw Cable 108.j.

The Raw Cable 108.j includes dual shielded cable elements and optionallya single coaxial line, for carrying the video signals which are highspeed differential data signals as well as auxiliary signals as definedby cable specifications, power and ground being included among theauxiliary signals. Alternatively, the raw cable may include dualshielded cable elements only, i.e. excluding any other wires between thevideo source device and the video sink device. A dual shielded cableelement may be a shielded twisted pair (STP), or a dual coaxial elementcomprising two coaxial lines whose shields are joined, each coaxial lineenclosing one shielded conductor.

Various embodiments of the Raw Cable 108.j are described below, coveringHDMI and DisplayPort specifications and using either coaxial or shieldedtwisted pair (STP) technology.

The Output Connector 112 connects the Raw Cable 108 to the Video SinkDevice (Rx) 106, and comprises an Output Paddle Board 116.j including aCable Boost Device 118, for providing connectivity between thefacilities (wires, shields) of the Raw Cable 108.j and the Video SinkDevice (Rx) 106. The Cable Boost Device 118 is connected between some ofthe wires of the cable and the input of the Video Sink Device (Rx) 106.The Cable Boost Device 118 includes a number of Boost Circuits 20, oneBoost Circuit 20 for terminating the dual shielded cable elements of theRaw Cable 108 which carry the high speed differential digital datasignals that arrive from the Video Source Device (Tx) 104 over the RawCable 108.

The Input Paddle Board 114.j and the Output Paddle Board 116.jconstitute first and second circuit carriers which are convenientlyconstructed as small printed circuit boards (PCB) and may be configuredto provide the mechanical support for connector contacts according tothe cable specification, for example according to the HDMI orDisplayPort standards.

FIG. 3 shows a Basic Coax HDMI Cable 102.1 based on coax technology,including a circuit carrier in the form of a first Input Paddle Board114.1, a first Raw Cable 108.1, and a first Output Paddle Board 116.1according to an embodiment of the invention. The first Raw Cable 108.1includes a total of nine individual coaxial lines arranged as four dualshielded cable elements, that is coax pairs 202, 204, 206 and 208, and asingle coaxial line 210. Each coax pair 202 to 208 comprises two coaxiallines with inner signal wires labeled as “a” and “b”, and two shieldswhich are joined together such that the joined shields form a singleconductive path. Thus, each of the coax pairs 202 to 208 provides threeelectrical connections, i.e. one differential connection (wires “a” and“b”) and one single-ended connection (the joined shields), as describedearlier (see FIG. 1B). The single coaxial line 210 provides only twoconductive paths, the inner signal wire “a” and the shield.

The Cable Boost Device 118 is comprised within the first Output PaddleBoard 116.1, and has high speed differential signal inputs D2(polarities D2+, D2−), D1 (D1+, D1−), D0 (D0+, D0−), and D3 (D3+, D3−)and corresponding boosted outputs C2 (polarities C2+, C2−), C1 (C1+,C1−), C0 (C0+, C0−), and C3 (C3+, C3−). In addition, the Cable BoostDevice 118 has ground and power inputs (GND, +5V), and a programminginput (Pgm). The programming input is used to program parameters of theCable Boost Device 118 in manufacturing. In normal operation this inputis not active, and is effectively grounded (connected to GND) through alow resistance within the Cable Boost Device 118.

HDMI signals may be classified as either high speed differential datasignals or auxiliary signals. The high speed differential data signalsinclude Transition Minimized Differential Signaling (TMDS) Data 0, TMDSData 1, TMDS Data 2, and TMDS Clock. The auxiliary signals are thefollowing single ended signals: Consumer Electronics Control (CEC),Serial Clock (SCL), Serial Data (SDA), Utility, Hot Plug Detect (HPD),and Serial Data (SDA). A +5V Power and a Digital Data Channel (DDC)/CECGround connection is also provided through the cable. The +5V Power andthe DDC/CEC Ground connections are included in the auxiliary signals forsimplicity here.

The signals from the Video Source Device (Tx) 104 are connected toterminals in an Input Connection Field 212 of the Basic Coax HDMI Cable102.1, and recovered at the opposite end of the cable with terminals ofan Output Connection Field 214 for transmission to the Video Sink Device(Rx) 106. Standard HDMI signal names and corresponding terminal labelsof the Input and Output Connection Fields 212 and 214 are listed inTable 1, which shows the preferred connection arrangement, or signaldesignations, for the Basic Coax HDMI Cable 102.1.

Referring to FIG. 3 and Table 1, each of the four HDMI high speeddifferential data signals, TMDS Data 0, TMDS Data 1, TMDS Data 2, andTMDS Clock, are routed through the Basic Coax HDMI Cable 102.1 asdescribed in the following:

The TMDS Data 2 differential signal, comprising TMDS Data2+ and TMDSData2− is:

-   -   connected from the Video Source Device (Tx) 104 to txD2+ and        txD2− terminals in the Input Connection Field 212;    -   routed in the first Input Paddle Board 114.1 to the input of the        raw cable, namely the inner signal wires “a” and “b” of the coax        pair 202;    -   routed through the inner signal wires “a” and “b” of the coax        pair 202 of the first Raw Cable 108.1;    -   coupled from the end of the first Raw Cable 108.1 to D2+ and D2−        inputs of the Cable Boost    -   Device 118 in the first Output Paddle Board 116.1; and    -   coupled from the C2+ and C2− outputs of the Cable Boost Device        118 to rxD2+ and rxD2− terminals in the Output Connection Field        214.

The other three HDMI high speed differential data signals (TMDS Data 0,TMDS Data 1, and TMDS Clock) are similarly connected, see Table 1.

The shields of the HDMI high speed data signals (TMDS Data0 Shield, TMDSData1 Shield, TMDS Data2 Shield, and TMDS Clock Shield), as well as theDDC/CEC Ground signal from the Video Source Device (Tx) 104 areconnected to terminals txD0s, txD1s, txD2s, txCKs, and txGnd of theInput Connection Field 212, and tied to an input common ground node 216in the first Input Paddle Board 114.1 whence the input common groundnode 216 is connected to the shield of the single coaxial line 210.

In the first Output Paddle Board 116.1, the shield of the single coaxialline 210 is connected to an output common ground node 218 which isfurther connected to the ground (GND) input of the Cable Boost Device118, and to shield and ground connections of the Video Sink Device (Rx)106, namely terminals rxD0s, rxD1s, rxD2s, and rxGnd. The TMDS ClockShield of the Video Sink Device (Rx) 106 is connected through a terminalrxCKs to the programming (Pgm) input of the Cable Boost Device 118, andso is indirectly grounded through the small resistance within the CableBoost Device 118. This allows the Cable Boost Device 118 to beprogrammed from the HDMI connector after the boosted cable is assembledwithout requiring any additional wire to access it. Alternatively, therxCKs terminal may be grounded directly at the output common ground node218 along with the other shield connections.

The remaining auxiliary signals (CEC, SCL, SDA, Utility, +5V Power, andHPD), are connected in the first Input Paddle Board 114.1 to terminalstxCEC, txSCL, txSDA, txUt, txPWR, and txHPD respectively. In the firstOutput Paddle Board 116.1, they are connected to terminals rxCEC, rxSCL,rxSDA, rxUt, rxPWR, and rxHPD respectively. Compared to the HDMI highspeed data signals which are boosted by the Boost Device 118, theseauxiliary HDMI signals are at a lower speed, bypass the Cable BoostDevice 118, and may be carried on the inner wires or over the shields ofthe coaxial lines as may be convenient. The “Utility” signal in thiscase is unused. However if it is necessary to include it, it may becarried on an additional inner wire or over the shield of a coaxial wireas may be convenient.

While four of the auxiliary signals CEC, SCL, +5V Power and HPD arecarried over the shields of the coax pairs 202 to 208, another auxiliarysignal (DDC/CEC Ground), to which also the shields of the TMDS signalsare tied) is carried over the shield of single coaxial line 210, and yetanother auxiliary signal (SDA), is carried over the inner signal wire“a” of the single coaxial line 210.

In the Basic Coax HDMI Cable 102.1, these remaining HDMI signals (exceptthe Utility signal) are carried over the cable as follows:

-   -   CEC from the terminal txCEC, over the combined shields of the        coax pair 202, to the terminal rxCEC;    -   SCL from the terminal txSCL, over the combined shields of the        coax pair 204, to the terminal rxSCL;    -   SDA from the terminal txSDA, over the inner wire “a” of the coax        210, to the terminal rxSDA;    -   +5V Power from the terminal txPWR, over the combined shields of        the coax pair 206, to the terminal rxPWR; and    -   Hot Plug Detect from the terminal txHPD, over the combined        shields of the coax pair 208, to the terminal rxHPD.

In the first Output Paddle Board 116.1 the +5V Power is also connectedto the power input (+5V) of the Boost Device 218.

TABLE 1 Preferred Signal Routing in Basic Coax HDMI Cable 102.1 BoostInput Boost De- Output Connec- Raw De- vice Connec- HDMI tion Cable viceOut- tion Signal Name 212 108.1 Input put 214 TMDS Data2 Shield txD2s210.shield --> --> rxD2s TMDS Data2+ txD2+ 202.a D2+ C2+ rxD2+ TMDSData2− txD2− 202.b D2− C2− rxD2− TMDS Data1 Shield txD1s 210.shield -->--> rxD1s TMDS Data1+ txD1+ 204.a D1+ C1+ rxD1+ TMDS Data1− txD1− 204.bD1− C1− rxD1− TMDS Data0 Shield txD0s 210.shield --> --> rxD0s TMDSData0+ txD0+ 206.a D0+ C0+ rxD0+ TMDS Data0− txD0− 206.b D0− C0− rxD0−TMDS Clock Shield txCKs 210.shield — — — Pgm --> rxCKs TMDS Clock+ txCK+208.a D3+ C3+ rxCK+ TMDS Clock− txCK− 208.b D3− C3− rxCK− DDC/CEC GroundtxGnd 210.shield GND --> rxGnd CEC txCEC 202.shield --> --> rxCEC SCLtxSCL 204.shield --> --> rxSCL SDA txSDA 210 --> --> rxSDA Utility txUtn/c — — rxUt +5 V Power txPWR 206.shield +5 V --> rxPWR Hot Plug DetecttxHPD 208.shield --> --> rxHPD

FIG. 4 shows a Basic STP HDMI Cable 102.2 based on Shielded Twisted Pair(STP) technology, including a second Input Paddle Board 114.2, a secondRaw Cable 108.2, and a second Output Paddle Board 116.2 according toanother embodiment of the invention.

The Input and Output Connection Fields 212 and 214, including therespective terminals remain unchanged from the Basic Coax HDMI Cable102.2. The second Raw Cable 108.2 comprises five Shielded Twisted Pairs(STPs) 302, 304, 306, 308, and 310, each comprising a shield and twosignal wires “a” and “b” as described in FIG. 1A. The allocation of thestandard HDMI signals to connections through the second Raw Cable 108.2is provided by configurations of the second Input and Output PaddleBoards 114.2 and 116.2 respectively.

The STPs 302, 304, 306, 308, and 310 of the second Raw Cable 108.2provide 15 (3×5) distinct conductive paths, compared to the 14 paths(3×4+1) of the first Raw Cable 108.1. Hence an additional path isavailable which is advantageously used in a modification of the signalassignments. This is illustrated in FIG. 4 as well as in Table 2 whichlists the preferred arrangement for the Basic STP HDMI Cable 102.2.

Because of the additional line available in the second Raw Cable 108.2,compared to the first Raw Cable 108.1, it is possible to use a shieldconnection (a common node 312 connected to the shield of the STP 308) toconnect the shields of all high speed signals (D0, D1, D2, and CK), anduse a separate shield connection (the shield of the STP 310) for theground connection.

The preferred assignments shown in Tables 1 and 2 are to some extentarbitrary, and may be adapted to best utilize the space on the paddleboards and the configurations of the respective connectors.

TABLE 2 Preferred Signal Routing in Basic STP HDMI Cable 102.2 BoostInput Boost De- Output Connec- Raw De- vice Connec- HDMI tion Cable viceOut- tion Signal Name 212 108.2 Input put 214 TMDS Data2 Shield txD2s308.shield --> --> rxD2s TMDS Data2+ txD2+ 302.a D2+ C2+ rxD2+ TMDSData2− txD2− 302.b D2− C2− rxD2− TMDS Data1 Shield txD1s 308.shield -->--> rxD1s TMDS Data1+ txD1+ 304.a D1+ C1+ rxD1+ TMDS Data1− txD1− 304.bD1− C1− rxD1− TMDS Data0 Shield txD0s 308.shield --> --> rxD0s TMDSData0+ txD0+ 306.a D0+ C0+ rxD0+ TMDS Data0− txD0− 306.b D0− C0− rxD0−TMDS Clock Shield txCKs 308.shield — — — Pgm --> rxCKs TMDS Clock+ txCK+308.a D3+ C3+ rxCK+ TMDS Clock− txCK− 308.b D3− C3− rxCK− DDC/CEC GroundtxGnd 310.shield GND --> rxGnd CEC txCEC 306.shield --> --> rxCEC SCLtxSCL 310 --> --> rxSCL SDA txSDA 310.b --> --> rxSDA Utility txUt n/c —— rxUt +5 V Power txPWR 302.shield +5 V --> rxPWR Hot Plug Detect txHPD304.shield --> --> rxHPD

In this embodiment of the invention, the raw cable includes STPs only,i.e. excluding any other wires between the video source device and thevideo sink device.

HEAC Capability

In a Supplement 2 to the HDMI specification version 1.4. dated Jun. 5,2009 cited above, a “HDMI Ethernet and Audio Return Channel” (HEAC) isspecified. The HEAC channel is carried in a HEAC-capable HDMI cable as adifferential data signal, i.e. positive and negative polarity signalsHEAC+ and a HEAC− respectively, which replace the Hot Plug Detect (HPD)signal and the previously unused “Utility” signal respectively of thestandard HDMI signal set. The HEAC channel is a passive channel whichdoes not require boosting by the Cable Boost Device 118. However, itdoes require careful control of its impedance and should therefore beenclosed in a shield, either by running each polarity in a coaxial line,or both polarities over a shielded twisted pair (STP).

Accordingly, only modified connectivity (adding the HEAC channel, withcontrolled impedance lines, replacing HPD and “Utility” signals) in thepaddle boards and in the raw cable are required to convert the basicHDMI Cables (102.1 and 102.2) to accommodate the HEAC channel.

FIG. 5 shows a HEAC-Capable Coax HDMI Cable 102.3 based on coaxtechnology, and capable of carrying an HEAC channel: including a thirdInput Paddle Board 114.3, a third Raw Cable 108.3, and a third OutputPaddle Board 116.3 according to yet another embodiment of the invention.

The signals of the HEAC-capable HDMI signal set from the Video SourceDevice (Tx) 104, are connected to a HEAC-capable Input Connection Field412 of the HEAC-Capable Coax HDMI Cable 102.3, and recovered at theopposite end of the cable with a HEAC-capable Output Connection Field414 for transmission to the Video Sink Device (Rx) 106. Themodifications of the HEAC-capable Input and Output Fields 412 and 414relate to name changes compared to the Input and Output Fields 212 and214, and reflect name changes of the terminals concerned: txUt, rxUt,txHPD, and rxHPD of the Input and Output Fields 212 and 214, becometxHEAC−, rxHEAC−, txHEAC+, and rxHEAC+ of the HEAC-capable Input andOutput Fields 412 and 414.

The third Raw Cable 108.3 comprises a total of ten individual coaxiallines arranged in four dual shielded cable elements, that is coax pairs402, 404, 406, and 408, for carrying high speed digital data signals,and another dual shielded cable element, that is a coax pair 410, forcarrying a differential auxiliary signal. Each coax pair 402 to 410includes two coaxial lines with inner signal wires labeled as “a” and“b”, and two shields which are joined together such that the joinedshields of each coax pair form a single conductive path. Thus, each ofthe coax pairs 402 to 410 provides three electrical connections, i.e.one differential connection (wires “a” and “b”) and one single-endedconnection (the joined shields), as described earlier (see FIG. 1B).

The assignments of the HDMI signals to the available cable connectionsin the third Input Paddle Board 114.3 and the third Output Paddle Board116.3 are similar compared to the assignments used in the first Inputand Output Paddle Boards 114.1 and 116.1 respectively. Unchangedconnections are those for the differential HDMI high-speed data channelsTMDS D2, D1, D0, and Clock, incoming from the Video Source Device 104,which are connected through the coax pairs 402, 404, 406, and 408respectively to corresponding inputs of the Cable Boost Device 118.

The differential HEAC channel is connected through the coax pair 410,and bypasses the Cable Boost Device 118. The shields of the coax pairs402, 404, 406, 408, and 410 serve as conductors for the HDMI signalsCEC, SCL, +5V Power, SDA, and DDC/CEC Ground respectively.

TABLE 3 Preferred Signal Routing in HEAC- capable Coax HDMI Cable 102.3Boost Input Boost De- Output Connec- Raw De- vice Connec- HDMI tionCable vice Out- tion Signal Name 212 108.2 Input put 214 TMDS Data2Shield txD2s 410.shield --> --> rxD2s TMDS Data2+ txD2+ 402.a D2+ C2+rxD2+ TMDS Data2− txD2− 402.b D2− C2− rxD2− TMDS Data1 Shield txD1s410.shield --> --> rxD1s TMDS Data1+ txD1+ 404.a D1+ C1+ rxD1+ TMDSData1− txD1− 404.b D1− C1− rxD1− TMDS Data0 Shield txD0s 410.shield -->--> rxD0s TMDS Data0+ txD0+ 406.a D0+ C0+ rxD0+ TMDS Data0− txD0− 406.bD0− C0− rxD0− TMDS Clock Shield txCKs 410.shield — — — Pgm --> rxCKsTMDS Clock+ txCK+ 408.a D3+ C3+ rxCK+ TMDS Clock− txCK− 408.b D3− C3−rxCK− DDC/CEC Ground txGnd 410.shield GND --> rxGnd CEC txCEC 402.shield--> --> rxCEC SCL txSCL 404.shield --> --> rxSCL SDA txSDA 408.shield--> --> rxSDA HEAC− txHEAC+ 410 --> --> rxHEAC− +5 V Power txPWR406.shield +5 V --> rxPWR HEAC+ txHEAC+ 410.b --> --> rxHEAC+

The incoming shields of the HDMI high-speed data channels TMDS D2, D1,D0, and the TMDS Clock, are tied to the DDC/CEC Ground connectionthrough the shield of the coax pair 410 of the cable, thus providing aconnection to the outgoing shields of the HDMI high-speed data channelsTMDS D2, D1, and D0. The outgoing shield of the TMDS Clock (rxCKs) isconnected to the programming pin (Pgm) of the Cable Boost Device 118 asdescribed above with reference to the Basic Coax HDMI Cable 102.1.

The preferred HDMI signal routing of the HEAC-Capable Coax HDMI Cable102.3 is listed in Table 3.

FIG. 6 shows a HEAC-Capable STP HDMI Cable 102.4, based on ShieldedTwisted Pair (STP) technology and capable of carrying an HEAC channel,including a fourth Input Paddle Board 114.4, a fourth Raw Cable 108.4,and a fourth Output Paddle Board 116.4 according to a fourth embodimentof the invention.

The HEAC-capable Input and Output Connection Fields 412 and 414 of theHEAC-Capable STP HDMI Cable 102.4, including the respective terminalsremain unchanged from the HEAC-Capable Coax HDMI Cable 102.3. The fourthRaw Cable 108.4 comprises five Shielded Twisted Pairs (STPs) 502, 504,506, 508, and 510, each comprising a shield and two signal wires “a” and“b” as described in FIG. 1A. The allocation of the HDMI signals toconnections through the fourth Raw Cable 108.4 is provided byconfigurations of the fourth Input and Output Paddle Boards 114.4 and116.4 respectively.

The STPs 502, 504, 506, 508, and 510 of the fourth Raw Cable 108.4provide 15 (3×5) distinct conductive paths, the same number as providedin the third Raw Cable 108.3. Accordingly, an analogous allocation ofthe individual signals to the Shielded Twisted Pairs including theirshields, could be made. Similarly, part of the allocation scheme couldalso be “borrowed” from the other STP based embodiment (the Basic STPHDMI Cable 102.2) and suitably modified to accommodate the HEAC signal.

A different connection allocation scheme is proposed here to illustratethe considerable latitude available in choosing configurations. Thepreferred assignments for the HEAC-Capable STP HDMI Cable 102.4 areillustrated in FIG. 6 as well as in Table 4.

As indicated earlier, the preferred assignments of signal leads in thecables are shown in the Tables 1, 2, 3, and 4. These are to some extentarbitrary. The “+5V Power” and the “DDC/CEC Ground” connections arepreferably carried on a shield; the HDMI high speed data signals (TMDSD0, D1, D2, and Clock) should always be carried on shielded conductors,i.e. the inner conductors of coax lines or the twisted signal wires ofSTPs, depending on wire type; and the lower speed connections (CEC, SCL,SDA, Utility, and HPD) may be carried on inner/signal wires or shieldsin an arrangement that may be adapted to best utilize the space on thepaddle boards and the configuration of the respective connectors.

The use of the TMDS Clock Shield connection on the receive side (rxCKs)to access the programming pin (Pgm) of the Cable Boost Device 118 is aconvenience for programming the device in the fully assembled boostedHDMI cable. If this feature is not required, the TMDS Clock Shieldshould be grounded along with the other TDMS signal shields at both endsof the cable.

TABLE 4 Preferred Signal Routing in HEAC- capable STP HDMI Cable 102.4Boost Input Boost De- Output Connec- Raw De- vice Connec- HDMI tionCable vice Out- tion Signal Name 212 108.2 Input put 214 TMDS Data2Shield txD2s 510.shield --> --> rxD2s TMDS Data2+ txD2+ 502.a D2+ C2+rxD2+ TMDS Data2− txD2− 502.b D2− C2− rxD2− TMDS Data1 Shield txD1s510.shield --> --> rxD1s TMDS Data1+ txD1+ 504.a D1+ C1+ rxD1+ TMDSData1− txD1− 504.b D1− C1− rxD1− TMDS Data0 Shield txD0s 510.shield -->--> rxD0s TMDS Data0+ txD0+ 506.a D0+ C0+ rxD0+ TMDS Data0− txD0− 506.bD0− C0− rxD0− TMDS Clock Shield txCKs 510.shield — — — Pgm --> rxCKsTMDS Clock+ txCK+ 508.a D3+ C3+ rxCK+ TMDS Clock− txCK− 508.b D3− C3−rxCK− DDC/CEC Ground txGnd 510.shield GND --> rxGnd CEC txCEC 506.shield--> --> rxCEC SCL txSCL 508.shield --> --> rxSCL SDA txSDA 504.shield--> --> rxSDA HEAC− txHEAC--> 510 --> --> rxHEAC− +5 V Power txPWR502.shield +5 V --> rxPWR HEAC+ txHEAC+ 510.b --> --> rxHEAC+

DisplayPort Cables

FIG. 7 shows a Coax DisplayPort Cable 102.5 based on coax technology,including a fifth Input Paddle Board 114.5, a fifth Raw Cable 108.5, anda fifth Output Paddle Board 116.5 according to an embodiment of theinvention. The fifth Raw Cable 108.5 includes a total of ten individualcoaxial lines arranged in five coax pairs 602, 604, 606, 608, and 610.Each coax pair 602 to 610 comprises two coaxial lines with inner signalwires labeled as “a” and “b”, and two shields which are joined togethersuch that the joined shields form a single conductive path. Thus, eachof the coax pairs 602 to 608 provides three electrical connections, i.e.one differential connection (wires “a” and “b”) and one single-endedconnection (the joined shields), as described earlier (see FIG. 1B).

The same Cable Boost Device 118 as in the boosted HDMI cables describedabove, is comprised within the fifth Output Paddle Board 116.5.

Standard DisplayPort signals from the Video Source Device (Tx) 104, areconnected to terminals in a DisplayPort Input Connection Field 612 ofthe Coax DisplayPort Cable 102.5, and recovered at the opposite end ofthe cable at terminals of a DisplayPort Output Connection Field 614 fortransmission to the Video Sink Device (Rx) 106. The DisplayPort signalnames and corresponding terminal labels of the DisplayPort Input andOutput Connection Fields 612 and 614 are listed in Table 5, which showsthe preferred connection arrangement, or signal allocation scheme, forthe Coax DisplayPort Cable 102.5.

Referring to FIG. 7 and Table 5, each of the four DisplayPort high speeddifferential data lanes ML-L0, ML-L1, ML-L2, and ML-L3, is routedthrough the Coax DisplayPort Cable 102.5 as described in the following:

The Main Line Lane0 differential signal, comprising positive (p) andnegative (n) polarities is:

-   -   connected from the Video Source Device (Tx) 104 to txML_L0+ and        txML_L0− terminals in the DisplayPort Input Connection Field        612;    -   routed in the fifth Input Paddle Board 114.5 to the inner signal        wires “a” and “b” of the coax pair 602;    -   routed through the fifth Raw Cable 108.5 on the inner signal        wires “a” and “b” of the coax pair 602 of the fifth Raw Cable        108.5;    -   coupled from the end of the fifth Raw Cable 108.5 to D0+ and D0−        inputs of the Cable Boost Device 118 in the fifth Output Paddle        Board 116.5; and    -   coupled from the C0+ and C0− outputs of the Cable Boost Device        118 to rxML_L0+ and rxML_L0− terminals in the DisplayPort Output        Connection Field 614.

The other three main-line differential data signals (Main Line Lane1,Lane2, and Lane 3) are similarly connected, see Table 5.

All ground connections of the incoming DisplayPort connector which arelabeled txGND0, txGND1, txGND2, txGND3, txGNDaux as well as the “Return”(txGNDpwr), i.e. the power return terminal, are tied together to aninput common ground node 616 in the fifth Input Paddle Board 114.5, andconnected to the shield of the coax pair 604.

In the fifth Output Paddle Board 116.5, the shield of the coax pair 604is connected to an output common ground node 618 which is also connectedto the ground (GND) input of the Cable Boost Device 118, and to shieldand ground connections of the Video Sink Device (Rx) 106, namelyterminals rxGND0, rxGND1, rxGND2, rxGNDaux, and txGNDpwr. An exceptionis the fourth ground pin of the receive side which is connected througha terminal rxGND3 to the programming (Pgm) input of the Cable BoostDevice 118, and so is only indirectly grounded. This allows the CableBoost Device 118 to be programmed from the connector after the boostedcable is assembled without requiring any additional wire to access it.Alternatively, the rxGND3 terminal may also be grounded at the outputcommon ground node 618 along with the other ground connections.

Other DisplayPort signals CONFIG1, CONFIG2, AUX Channel (p) and (n), HotPlug, and DP_PWR, are respectively connected in the fifth Input PaddleBoard 114.5 to terminals txCONFIG1, txCONFIG2, txAuxCh+ and txAuxCh−,txHPD, and txDP_PWR. In the fifth Output Paddle Board 116.5. they arerespectively connected to terminals rxCONFIG1, rxCONFIG2, rxAuxCh+ andrxAuxCh−, rxHPD, and rxDP_PWR. Compared to the main line high speedsignals which are boosted by the Boost Device 118, these otherDisplayPort signals are at a lower speed, bypass the Cable Boost Device118, and may be carried on the inner wires or over the shields of thecoaxial lines as may be convenient. The AUX Channel signal however is ofmoderately high speed and is required to be carried in a controlledimpedance wire, for which the coax pair 610 is chosen in this embodimentof the invention.

In the Coax DisplayPort Cable 102.5, the remaining signals are carriedover the cable as follows:

-   -   CONFIG1 from the terminal txCONFIG1, over the combined shields        of the coax pair 606, to the terminal rxCONFIG1;    -   CONFIG2 from the terminal txCONFIG2, over the combined shields        of the coax pair 608, to the terminal rxCONFIG2;    -   Hot Plug from the terminal txHPD, over the combined shields of        the coax pair 610, to the terminal rxHPD; and    -   DP_PWR from the terminal txDP_PWR, over the combined shields of        the coax pair 602, to the terminal rxDP_PWR.

In the fifth Output Paddle Board 116.5 the DP_PWR is also connected tothe power input (+5V) of the Cable Boost Device 218. Even though thevoltage of DP_PWR will be lower than the HDMI +5V Power, the same CableBoost Device 218 may be designed or programmed to run at both the HDMIand the DisplayPort voltages. Alternatively, a DisplayPort specificversion of the Cable Boost Device 218 may be developed.

TABLE 5 Preferred Signal Routing in Coax DisplayPort Cable 102.5 BoostInput Boost De- Output Connec- Raw De- vice Connec- DisplayPort tionCable vice Out- tion Signal Name 212 108.1 Input put 214 Main Line Lane0txML_L0+ 602 D0+ C0+ rxML_L0+ (p) Ground (pin 2) txGND0 604.shield -->--> rxGND0 Main Line Lane0 txML_L0− 602.b D0− C0− rxML_L0− (n) Main LineLane1 txML_L1+ 604 D1+ C1+ rxML_L1+ (p) Ground (pin 5) txGND1 604.shield--> --> rxGND1 Main Line Lane1 txML_L1− 604.b D1− C1− rxML_L1− (n) MainLine Lane2 txML_L2+ 606 D2+ C2+ rxML_L2+ (p) Ground (pin 8) txGND2604.shield --> --> rxGND2 Main Line Lane2 txML_L2− 606.b D2− C2−rxML_L2− (n) Main Line Lane3 txML_L3+ 608 D3+ C3+ rxML_L3+ (p) Ground(pin 11) txGND3 604.shield Pgm --> rxGND3 Main Line Lane0 txML_L3− 608.bD3− C3− rxML_L3− (n) CONFIG1 txCONFIG1 606.shield --> --> rxCONFIG1CONFIG2 txCONFIG2 608.shield --> --> rxCONFIG2 AUX Channel (p) txAuxCh+610 --> --> rxAuxCh+ Ground (pin 16) txGNDaux 604.shield --> -->rxGNDaux AUX Channel (n) txAuxCh− 610.b --> --> rxAuxCh− Hot Plug txHPD610.shield --> --> rxHPD Return txGNDpwr 604.shield GND --> rxGNDpwrDP_PWR txDP_PWR 602.shield +5 V --> rxDP_PWR

FIG. 8 shows a STP DisplayPort Cable 102.6 based on Shielded TwistedPair (STP) technology, including a sixth Input Paddle Board 114.6, asixth Raw Cable 108.6, and a sixth Output Paddle Board 116.6 accordingto an embodiment of the invention. The sixth Raw Cable 108.6 includes atotal of five STPs 702, 704, 706, 708, and 710, each comprising a shieldand two signal wires “a” and “b” as described in FIG. 1A.

The allocation of the DisplayPort signals to connections through thesixth Raw Cable 108.6 is provided by configurations of the sixth Inputand Output Paddle Boards 114.6 and 116.6 respectively, and is analogousto the allocation in the Coax DisplayPort Cable 102.5, FIG. 7. The STPsignal assignments are illustrated in FIG. 8 which is identical to FIG.7 except for showing Shielded Twisted Pairs (STPs) 702, 704, 706, 708,and 710 instead of coax pairs 602-610. While the sixth Input and OutputPaddle Boards 114.6 and 116.6 have similar connectivity to thecorresponding fifth Input and Output Paddle Boards 114.5 and 116.5,their mechanical properties would differ in order to accommodate thedifferent termination geometries of the STPs versus the coax pairs onthe paddle boards.

All auxiliary signals, CONFIG1, CONFIG2, Hot Plug, Ground and DP_PWR,may be placed over any shields of coaxial or STP lines as may beconvenient or for an arrangement that may be adapted to best utilize thespace on the paddle boards and the configuration of the respectiveconnectors.

Low Wire Count Summary

The number of wires in a boosted high speed digital video cable such asan HDMI or DisplayPort cable, has been reduced from fourteen or more inprior art cables to nine or ten by using the shields to individuallycarry active signals as well as power and ground. This reduction isenabled by the boost device which guarantees the removal of potentiallyharmful common mode interference on the high speed data lines. Thereduction in the number of wires simplifies their alignment fortermination in the connectors. The original high speed cables use a mixof coaxial lines or shielded twisted pairs and standard wires. Theinvention provides a reduction in the construction cost of high speedcables by the use of only a single type of wire, either coaxial or STP,to carry all signals. This significantly simplifies cable assembly andallows a single step termination process, ultimately reducing cost.

Low Impedance Cables

In addition to the advantages obtained through the low wire counttechnique described above, a further cost advantage may be achieved byusing coaxial lines or Shielded Twisted Pairs (STP) of a lower impedancethan the nominal line impedance implied in the standards, for carryingthe high speed data signals in any of the Boosted Digital Video Cables102 described here.

FIG. 9 shows a three coax line cross sections, to illustrate acomparison between exemplary design choices, including a standard coax902; a reduced-outer-diameter coax 904; and an increased-core-diametercoax 906. The standard coax 902 comprises an outer insulating sheath902.a, a shield 902.b, an inner insulator 902.c, and a core wire (core)902.d.

The reduced-outer-diameter coax 904 comprises an outer insulating sheath904.a, a shield 904.b, an inner insulator 904.c, and a core wire (core)904.d. The increased-core-diameter coax 906 comprises an outerinsulating sheath 906.a, a shield 906.b, an inner insulator 906.c, and acore wire (core) 906.d.

The characteristic impedance Z0 of a coaxial line is determined bydimensions of the cable, more precisely, by the ratio of the diameter ofthe core wire to the inner diameter of the shield, and by the dielectricconstant of the inner isolator material.

The core 902.d of the thin standard coax 902 with a characteristicimpedance of 50 ohms is an American Wire Gauge (AWG) wire of about 78 μmdiameter, resulting in an overall diameter of the standard coax 902 ofabout 210 μm.

By allowing the coax to have a lower, “non-standard” characteristicimpedance it is possible for example, and without changing the insulatormaterial, to either reduce the outer diameter of the coax without havingto use a finer core wire, or to increase the core diameter while keepingthe outer diameter constant.

The core 904.d of the reduced-outer-diameter coax 904 is the same wiregauge as the core 902.d of the standard coax 902, but the shield 904.cis shrunk such that a characteristic impedance of 35 ohms is obtainedfor the reduced-outer-diameter coax 904. This results in an overalldiameter of the reduced-outer-diameter coax 902 of about 145 μm, asavings of about 30% compared to the standard coax 902 with 50 ohmcharacteristic impedance.

If the outer diameter is not changed, a thicker core wire may be used.The shield 906.b, hence the overall diameter of theincreased-core-diameter coax 906, corresponds to that of the standardcoax 902. However, the thickness of the core 906.d is increased suchthat a characteristic impedance of 35 ohms is obtained for theincreased-core-diameter coax 906, resulting in a wire size of AWG 40 forthe core 906.d of the increased-core-diameter coax 906. AWG 35corresponds to a wire diameter of about 143 μm, an almost 80% increasein thickness.

The inventors have considered the impact of deviating from the standard50 ohm coax for implementing the HDMI and DisplayPort cables describedabove, that is the Basic Coax HDMI Cable 102.1, the HEAC-Capable CoaxHDMI Cable 102.3, and the Coax DisplayPort Cable 102.5, as well as otherboosted digital video cables. To recapitulate, the Video Source Device104 transmits high speed differential signals through coax pairs to theCable Boost Device 118 which equalizes and boosts the signals beforetransmitting them to the Video Sink Device 106.

The Video Source Device 104 is designed to transmit these high speeddifferential signals over cables presenting a characteristic impedanceof 100 ohms differentially, that is 2 times 50 ohms in the case of dualcoaxial lines (coax pairs). An input circuit in the Video Sink Device106 similarly presents matching 100 ohms differential terminations tothe cable.

In the case of the boosted cables with a reduced impedance coax, theCable Boost Device 118 provides a proper output circuit for transmissionof the boosted signals to the Video Sink Device 106. An inputtermination in the Cable Boost Device 118 can be tuned to terminate areduced impedance cable with the correct impedance, for example 35 ohms,or 70 ohms differentially.

The Video Source Device 104 is designed as a current source and would beable to directly transmit into any cable impedance; no undesired signalreflections would result as long as the cable is correctly terminated atthe receiving end, that is at the Cable Boost Device 118. However,compliance testing of HDMI and DisplayPort cables requires the cable topresent a nominal 100 ohm differential impedance at source end for aunidirectional active cable and both ends for a passive cable.

FIG. 10 shows a Low-Impedance (Low Z0) Coax HDMI Cable 102.10 which isidentical to the Basic Coax HDMI Cable 102.1 of FIG. 3 except for aLow-Impedance Input Paddle Board 114.10 which replaces the first InputPaddle Board 114.1. The Low-Impedance Input Paddle Board 114.10 has thesame connectivity as the first Input Paddle Board 114.1, except foreight padding resistors R1 to R8 which are inserted between the highspeed signal terminals txD2+, txD2−, txD1+, txD1−, txD0+, txD02−, txCK+,and txCK− of the Input Connection Field 212, and the inner signal wires“a” and “b” of the corresponding coax pairs 202 to 208 of the first RawCable 108.1.

One pair of padding resistors is required to be inserted in series witheach of the inner signal wires “a” and “b” of the TMDS signals. Theresistance of each padding resistor is derived such that the combinedresistance of two padding resistors in series with the inner signalwires (the shielded conductors) of each coax pair (dual shielded cableelement) 202 to 208 is equal to the difference between the specifiednominal cable impedance and the impedance of the coax pair, for examplea 100 ohm nominal impedance is achieved by using two coax lines of 35ohm impedance, each with 15 ohm padding resistors, as a coax pair.

The padding resistors R1-R8 could be omitted without loss offunctionality, but they are provided in order to meet the specifieddifferential input impedance of 100 ohms for the Low-Impedance Coax HDMICable 102.10.

If the coax pairs 202 to 208 of the first Raw Cable 108.1 are made oflow-impedance coaxial lines, such as the reduced-outer-diameter coax 904or the increased-core-diameter coax 906 which each have an exemplarycharacteristic impedance of 35 ohms, the values of each of the paddingresistors R1 to R8 should be 50−35=15 ohms, such that each coax pair,combined with the padding resistors, presents a 2×50=100 ohm impedanceto the differential terminals of the Input Connection Field 212. Ingeneral, the resistance of each padding resistor R1 to R8 should be Xohms, where X is equal to the difference between one half of thespecified nominal impedance (e.g. 100 Ohms for HDMI) and the actualcharacteristic impedance of the coax.

Similarly, other coax based high speed video cables such as theHEAC-Capable Coax HDMI Cable 102.3 (FIG. 5) and the Coax DisplayPortCable 102.5 (FIG. 7) are easily modified by the addition of the paddingresistors R1 to R8 on their respective input paddle boards, toaccommodate low-impedance coax cables.

It is worth noting that signals other than the high speed differentialdata signals, for example the HEAC channel of HDMI and the AUX channelof DisplayPort, are not boosted by the Cable Boost Device 118. The coaxpairs transporting these signals (coax pair 410 for HEAC, and coax pair610 for the AUX channel) can not be of the low-impedance type, but mustbe regular 50 ohm coaxes. Alternatively, these signals may be carriedover low-impedance type coax if appropriate padding resistors areprovided at both the input and the output Paddle Boards. This concept isnot illustrated here, but will be described further below (FIG. 15).

The same techniques for using reduced impedance coax cables also appliesfor boosted HDMI and DisplayPort cables that use Shielded Twisted Pairs(STP) for transmitting the high speed differential data signals. Thecharacteristic impedance of STPs is determined by the ratio of theinsulated wire diameter to the diameter of the bare wire, and thedielectric properties of the insulation material.

Low-impedance STPs are easily made by reducing the thickness of theinsulation compared to the diameter of the bare wire. This of coursealso affects the size of the shield. A reduction in the thickness of STPwire insulation by about 30% without changing the bare wire thicknesswill reduce the (differential) impedance of the STP from a nominal 100ohms to 70 ohms. Instead of reducing the size of the STP cable in thisway, it is also possible to maintain the original overall size andincrease the bare wire thickness.

When a low impedance STP is employed in any of the boosted video cablesbased on STP technology, such as the Basic STP HDMI Cable 102.2 (FIG.4), the HEAC-Capable STP HDMI Cable 102.4 (FIG. 6), and the STPDisplayPort Cable 102.6, the same considerations as with the coax basedcables apply: the input circuit of the Cable Boost Device 118 should beprogrammed to match the STP impedance, and the input paddle board shouldbe modified to include padding resistors. Similar to the rule thatapplies in the coax case, the resistance of each padding resistor R1 toR8 in the STP case should be Y ohms, where Y is equal to one half of thedifference between the specified nominal impedance (e.g. 100 Ohms forHDMI) and the actual differential impedance of the STP.

The lowering of the characteristic impedance in coax or STP based cableswhich include boost devices has a number of advantages which may beexploited, either to reduce the size of the cable for material savings,improved flexibility, etc., or to increase the wire size withoutreducing the overall size of the cable for improved handling, and lowermaterial cost. Note that thicker wire may actually cost less to producethan very fine wire.

Based on the Basic Coax HDMI Cable 102.1, a further number of inventiveconcepts are disclosed which may be used separately or in combinationsto improve the economic value of high speed data cables, including:

-   -   a boosted video cable, comprising a raw cable with higher        impedance (FIG. 11);    -   reducing the wire count by splitting coax pairs into individual        coax lines (FIG. 12A);    -   reducing the wire count by carrying a high speed signal single        ended (FIG. 12B);    -   reducing the wire count by carrying a signal on the cable's        braid (FIG. 13B and FIG. 14);    -   providing previously described advantages in a cable without a        boost device (FIGS. 15 to FIG. 24).        Boosted Video Cable with High Impedance Raw Cable

In some cases, there may be an advantage to manufacture cables withcoaxial lines of a higher impedance than the nominal impedance of 50ohms. Similarly, STPs of a higher differential impedance than thenominal impedance of 100 ohms may be advantageous. These may bevaluable, for example to reduce loss in the case of a tinned copperconductor material, by increasing the size of the insulation whichincreases the impedance of the raw cable.

As mentioned already, the Video Source Device 104 is designed totransmit high speed differential signals over cables presenting acharacteristic impedance of 100 ohms differentially, that is 2 times 50ohms in the case of dual coaxial lines (coax pairs), or over STPs ofnominal 100 ohms impedance.

The Cable Boost Device 118 provides a proper impedance output circuitfor transmission of the boosted signals to the Video Sink Device 106. Aninput termination in the Cable Boost Device 118 can be tuned toterminate an increased impedance cable with the correct raw-cableimpedance, for example over the range of 60 ohms to 150 ohmsdifferentially.

However, compliance testing of HDMI and DisplayPort cables requires thecable to present a nominal 100 ohm differential impedance at the sourceend of a unidirectional active cable, such as a boosted cable.

FIG. 11 shows a High-Impedance (High Z0) Coax HDMI Cable 102.11 which isidentical to the Basic Coax HDMI Cable 102.1 of FIG. 3 except for aHigh-Impedance Input Paddle Board 114.11 replacing the first InputPaddle Board 114.1. The High-Impedance Input Paddle Board 114.11 has thesame connectivity as the first Input Paddle Board 114.1, except for theaddition of four shunt resistors R9 to R12 which are connected betweenthe high speed signal terminals of respectively the pairs (txD2+,txD2−), (txD1+, txD1−), (txD0+, txD02−), and (txCK+, and txCK−) of theInput Connection Field 212.

The resistance of each shunt resistor is derived such that the combinedresistance of each padding resistor R9 to R12 in parallel with theimpedance of the corresponding coax pair (dual shielded cable element)202 to 208 is equal to the specified nominal cable impedance. Forexample, where the cable is comprised of coax pairs, each individualcoax line having an impedance of Z0=75 ohms, the 100 ohm nominaldifferential impedance at the cable input may be achieved with 300 ohmshunt resistors as illustrated in FIG. 11. In general, the value of eachshunt resistor Rx (R9 to R12) may be calculated as:

Rx=1/((1/Zn)−(1/(2*Z0))),

where Z0 is the impedance of the individual coax line, and Zn is thedesired differential input impedance of the cable, that is, the inverseof the resistance of the shunt resistor is equal to the differencebetween the inverse of the nominal impedance Zn and the inverse of thedifferential impedance of the coax pair which is twice the impedance Z0of one coaxial line.

The shunt resistors R9 to R12 could be omitted without loss offunctionality, but they are provided in order to meet the specifieddifferential input impedance of 100 ohms for the High-Impedance CoaxHDMI Cable 102.11.

Similarly, other coax based high speed video cables such as theHEAC-Capable Coax HDMI Cable 102.3 (FIG. 5) and the Coax DisplayPortCable 102.5 (FIG. 7) are easily modified by the addition of the shuntresistors R9 to R12, placed across respective high speed differentialsignals on their respective input paddle boards, to accommodate higherimpedance coax cables.

It is worth noting that signals other than the high speed differentialdata signals, for example the HEAC channel of HDMI and the AUX channelof DisplayPort, are not boosted by the Cable Boost Device 118. The coaxpairs transporting these signals (the coax pair 410 for HEAC, and thecoax pair 610 for the AUX channel) can not be of the high-impedancetype, but must be regular 50 ohm coaxes. Alternatively, these signalsmay be carried over high-impedance type coax if appropriate shuntresistors are provided at both the input and the output Paddle Boards.This concept is not illustrated here.

The same techniques for using increased impedance coax cables may alsobe applied for boosted HDMI and DisplayPort cables that use ShieldedTwisted Pairs (STP) for transmitting the high speed differential datasignals. The characteristic impedance of STPs is determined by the ratioof the insulated wire diameter to the diameter of the bare wire, and thedielectric properties of the insulation material.

High-impedance STPs are easily made by increasing the thickness of theinsulation compared to the diameter of the bare wire. This of coursealso affects the size of the shield. An increase in the thickness of STPwire insulation by about 30% without changing the bare wire thicknesswill increase the differential impedance of the STP from a nominal 100ohms to 150 ohms. Instead of increasing the size of the STP cable inthis way, it is also possible to maintain the original overall size anddecrease the bare wire thickness of the twisted wires.

When a high impedance STP is employed in any of the boosted video cablesbased on STP technology, such as the Basic STP HDMI Cable 102.2 (FIG.4), the HEAC-Capable STP HDMI Cable 102.4 (FIG. 6), and the STPDisplayPort Cable 102.6, the same considerations as with the coax basedcables apply: the input circuit of the Cable Boost Device 118 should beprogrammed to match the STP impedance, and the respective input paddleboards should be modified to include the shunt resistors R9 to R12.

As illustrated in FIGS. 10 and 11, a corrected effective impedance ofthe cable, or measured cable input impedance, which is substantiallyequal to the nominal impedance of the digital video cable specified inthe cable specification, is achieved using resistor networks of seriesor shunt resistors respectively, and thus permits the use of low or highimpedance raw cables respectively.

Additional Reduced Wire Count Techniques

For economic reasons, it is desirable to reduce the number of coaxiallines while still carrying all required signals. The technique ofcarrying a low speed signal in the joined shields of a dual shieldedcable element has been described above, for example using the joinedshields of the dual shielded cable element 202 (FIG. 3) for carrying theCEC signal. This has resulted in a design in which nine coaxial lines(four dual shielded cable elements and a single coax line) carryfourteen HDMI signals.

In order to further reduce the number of coaxial lines to eight, andstill carry fourteen HDMI signals, the inventors propose to split two ofthe dual shielded cable element into split dual shielded cable elements.

A split dual shielded cable element comprises two coax lines whoseshields are not galvanically joined, but only coupled to each otherthrough a capacitor providing AC coupling. At the same time each shieldprovides an independent capability of carrying a low speed signal.

FIG. 12A shows a basic configuration 1200 of a split dual shielded cableelement 1202 including two coax lines 1204 and 1206, analogous to thedual coaxial element 12B of FIG. 1 b for carrying the differentialsignal “D” which includes the polarities D+i and D−i. But instead ofjoining the shields of the two coax lines 1204 and 1206 galvanically,they are only joined in a high-frequency coupling or capacitive couplingthrough a coupling capacitor Cs, connected to the shields at the inputsof the two coax lines 1204 and 1206. This allows two independentsingle-ended signals A1 and A2 to be carried on the respective shieldswhile still preserving the transmission characteristics of the dualshielded cable element with respect to the differential data signal “D”which is a high-speed signal.

In the split dual shielded cable element 1202, crosstalk from theshields to the inner conductors carrying the differential signal is nolonger automatically cancelled, and it is necessary to carefully selectwhich connections should be carried on the shields. Preferably onlystatic signals such as power and ground should be carried, or the innerconductor(s) may be used to carry the clock signal which is of lowerspeed than the other high speed signals, and which can be recovered moreeasily even if it is impacted by some cross talk.

On one hand, the capacitance of the coupling capacitor Cs is chosen tobe high enough to preserve transmission characteristics of the dualshielded cable element with respect of the high speed differentialsignal, including providing A/C coupling between the individual shieldsto be substantially the same as a galvanic connection between a commonshield of a dual shielded element. On the other hand, the capacitance ofthe coupling capacitor Cs is chosen to be low enough not to cause crosstalk between low speed auxiliary signals.

The differential signal from the output of the split dual shielded cableelement 1202 is coupled to the boost circuit, while the single-endedsignals (A1) and (A2) are simply forwarded. A second (optional) couplingcapacitor Co may be used to couple the shields of the coax lines 1204and 1206 to one another at the cable output. The value of the couplingcapacitor Cs (and Co if used) is preferably of the order of 1 nF, toprovide an effective AC-short between the shields thus providingsubstantially the same coupling (with respect to high speed signals) asthe galvanic connection of FIG. 1B. This has the effect of adding the(single-ended) impedances of the two coax lines to provide their sum asa differential impedance. At the same time, the coupling capacitor Csprovides negligible coupling between the single-ended signals A1 and A2which may be DC signals such as power and ground, or low-speed,quasi-static signals such as the HDMI HPD and CEC signals.

FIG. 12B illustrates a First 8-Coax HDMI Cable 102.12 including a First8-Coax Input Paddle Board 114.12, a First 8-Coax Raw Cable 108.12, and aFirst 8-Coax Output Paddle Board 116.12, as well as the Input and OutputConnection Fields 212 and 214.

The First 8-Coax HDMI Cable 102.12 incorporates two split dual shieldedcable elements 1208 and 1210 each comprising two coax lines (1208A and1208B, and 1210A and 1210B respectively) in the First 8-Coax Raw Cable108.12 and corresponding coupling capacitors C1 and C2 mounted on theFirst 8-Coax Input Paddle Board 114.12.

The First 8-Coax Raw Cable 108.12 further includes two dual shieldedcable elements, that is coax pairs 1212 and 1214.

The First 8-Coax Input and Output Paddle Boards 114.12 and 116.12respectively are arranged to provide connectivity between the Input andOutput Connection Fields 212 and the First 8-Coax Raw Cable 108.12.Where the First 8-Coax Raw Cable 108.12 is constructed withlow-impedance coax lines, the First 8-Coax Input Paddle Board 114.12 mayinclude padding resistors R13 to R20, analogous to the padding resistorsR1 to R8 of FIG. 10, each padding resistor connected in series between aTMDS signal or clock terminal of the Input Connection Field 212 and oneof the eight shielded conductors of the dual shielded cable elements orthe split dual shielded cable elements.

The resistance value of each of the padding resistors R13 to R20 isdetermined as the difference between one half of the nominaldifferential impedance of the First 8-Coax HDMI Cable 102.12, that is100 ohms for each of the high speed differential data signals, and theimpedance of each of the coaxial lines. For example, when 35-ohm coaxlines are used in the First 8-Coax Raw Cable 108.12, each paddingresistor (R13 to R20) should have a resistance of 15 ohms, so that thenominal differential HDMI impedance of 100 ohms is present at the InputConnection Field 212.

The padding resistors R13 to R20 are omitted when 50-ohm coax lines areused. Alternatively (not shown in FIG. 12B), shunt resistors analogousto the shunt resistors R9 to R12 of FIG. 11 would be used if coax linesof a higher impedance than 50 ohms are used in the First 8-Coax RawCable 108.12.

A preferred signal routing in the First 8-Coax HDMI Cable 102.12 isillustrated in FIG. 12B and shown in Table 6 below. The differentialTMDS Data signals and the TMDS Clock signal are coupled through thepadding resistors R13 to R20 to the inner (shielded) conductors of theeight coax lines.

The galvanically joined shields of the dual shielded cable elements 1212and 1214 are connected in the paddle boards to carry respectively thelow-speed HDMI signals SCL and SDA.

The shields of the four coax lines 1208A, 1208B, 1210A, and 1210B of thetwo split dual shielded cable elements 1208 and 1210 are connected tocarry respectively four static, or predominantly static low speedsignals having have substantially static properties, namely: DDC/CECGround; +5V Power; CEC; and HPD. The proposed signal assignments of theFirst 8-Coax HDMI Cable 102.12, shown in FIG. 12B and in Table 6 beloware merely examples, and different assignments are equally possible.

TABLE 6 Preferred Signal Routing in First 8-Coax HDMI Cable 102.12 BoostInput Boost De- Output Connec- Raw De- vice Connec- HDMI tion Cable viceOut- tion Signal Name 212 108.12 Input put 214 TMDS Data2 Shield txD2s1208A.shield --> --> rxD2s TMDS Data2+ txD2+ 1212.a D2+ C2+ rxD2+ TMDSData2− txD2− 1212.b D2− C2− rxD2− TMDS Data1 Shield txD1s 1208A.shield--> --> rxD1s TMDS Data1+ txD1+ 1214.a D1+ C1+ rxD1+ TMDS Data1− txD1−1214.b D1− C1− rxD1− TMDS Data0 Shield txD0s 1208A.shield --> --> rxD0sTMDS Data0+ txD0+ 1208.a D0+ C0+ rxD0+ TMDS Data0− txD0− 1208.b D0− C0−rxD0− TMDS Clock Shield txCKs 1208A.shield — — — Pgm --> rxCKs TMDSClock+ txCK+ 1210.a D3+ C3+ rxCK+ TMDS Clock− txCK− 1210.b — C3− rxCK−DDC/CEC Ground txGnd 1208A.shield GND --> rxGnd CEC txCEC 1210A.shield--> --> rxCEC SCL txSCL 1212.shield --> --> rxSCL SDA txSDA 1214.shield--> --> rxSDA Utility txUt n/c — — rxUt +5 V Power txPWR 1208B.shield +5V --> rxPWR Hot Plug Detect txHPD 1210B.shield --> --> rxHPD

Single Ended Clock Concept

A concept of advantageously carrying an originally differential highspeed signal as a single-ended signal is also illustrated in FIG. 12B.The First 8-Coax Output Paddle Board 116.12 includes a Modified BoostDevice 118.12, modified from the Boost Device 118 by omitting thenegative polarity input D3− of the high speed differential signal inputD3. Although only a single ended TMDS clock signal (txCK+->D3+) is thusreceived by the Modified Boost Device 118.12, the Modified Boost Device118.12 includes a single-ended to differential converter (SDC) 1216 inwhich the single ended clock input D3+ is converted to a differentialsignal, and a differential output is generated at the C3+ and C3−outputs of the Modified Boost Device 118.12. The regenerateddifferential clock signals (C3+, C3−) are coupled through the OutputConnection Field 214 to the output of the First 8-Coax HDMI Cable 102.12as rxCK+ and rxCK−, and thus the Video Sink Device 106 receives astandard differential clock.

The high speed TMDS Clock signal is received from the Video SourceDevice at the terminals txCK+ and txCK−, and transmitted through thepadding resistors R19 and R20, to the inner conductors of the coax lines1210A and 1210B respectively of the split dual shielded cable element1210. Only the positive polarity of the clock signal corresponding totxCK+ is coupled from the output of the inner conductor of the coax line1210A to the D3+ input of the Modified Boost Device 118.12. The negativepolarity of the signal is terminated at the output from the innerconductor of the coax line 1210B on a terminating resistor R21, theterminating resistor R21 being connected to a common output ground node1218 of the First 8-Coax Output Paddle Board 116.12. The resistancevalue of the terminating resistor R21 should match the impedance of thecoax line 1210B, which may be for example 35 ohms.

The single ended clock concept advantageously exploits the fact that theVideo Source Device 104 drives a differential current mode signal whichis designed to be terminated in an input circuit of the Video SinkDevice 106 (or a boost device) to provide terminating pull-up resistorsconnected to a bias voltage to each of the two lines of the differentialsignal path. However in the proposed single ended clock concept, onlyone of the two lines of the differential signal path is biased by aterminating pull-up resistor in the boost device, the other line beinggrounded through an external resistor and thus becoming inactive. As aresult, the clock signal, although nominally generated as a differentialsignal, travels as a single ended signal. Several advantages may beobtained from this embodiment: the shield of the single ended clock linetxCK+ is used to carry the HPD signal which is normally completelystatic, and thus no interference is coupled from this shield to txCK+;one external signal pin is saved in the boost device; and less currentneeds to be supplied by the boost device for receiving the single endedsignal compared to a differential signal, thus leaving more poweravailable for other functions of the boost device.

While the termination resistor R21 is preferably realized as a componenton the First 8-Coax Output Paddle Board 116.12, it may also be containedin the boost device instead. The termination resistor R21 may be anactual resistor or a resistance element otherwise realized, and may alsobe referred to as a termination element.

In some applications the SDC 1216 may also be realized independently ofthe boost device and can so also be used without the boost device in acable where boosting of other high speed signals is not required.

Carrying a Signal on the Cable Braid

FIG. 13A illustrates an expanded generic diagram 1300 of the genericBoosted Digital Video Cable 102.j of FIG. 2, including: the Raw Cable108.j comprising a Metallic Outer Cable Braid also referred to simply as“Outer Braid”, or “Braid” 1302 which encloses signal lines of varioustypes; the Input Connector 110 comprising a metallic Input ConnectorShell 1304 which partially encloses the Input Connection Field 212 andthe Input Paddle Board 114.j; and the Output Connector 112 comprising ametallic Output Connector Shell 1306 which partially encloses the OutputConnection Field 214 and the Output Paddle Board 116.j. The MetallicOuter Cable Braid 1302 provides a galvanic connection between the InputConnector Shell 1304 and the Output Connector Shell 1306, and providesElectromagnetic Interference (EMI) shielding to the entire cableassembly. Normally, the Connector Shells 1304 and 1306 are grounded, andconnected with each other through the braid.

The cable braid also provides an electrical path from the inputconnector to the output connector. In a “Signal on the Braid” conceptdescribed below, the cable braid is used in an alternative cableconfiguration to carry one of the HDMI signals, allowing fourteen HDMIsignals to be carried in a cable comprising only eight coax lines.

FIG. 13B illustrates a general diagram of a Second 8-Coax HDMI Cable102.13, which includes a Second 8-Coax Input Paddle Board 114.13, aSecond 8-Coax Raw Cable 108.13, and a Second 8-Coax Output Paddle Board116.13. The Second 8-Coax Raw Cable 108.13 includes the Metallic OuterCable Braid 1302, and the Second 8-Coax Input Paddle Board 114.13 andthe Second 8-Coax Output Paddle Board 116.13 are partially enclosed inthe Input and Output Connector Shells 1304 and 1306 of the Input andOutput Connectors 110 and 112 respectively.

Instead of being directly joined to the metallic shells, as shown inFIG. 13A, the Metallic Outer Cable Braid 1302 is connected to the Inputand Output Connector Shells 1304 and 1306 through isolating capacitorsC3 and C4 of 0.1 to 1.0 μF, mounted on the Second 8-Coax Input andOutput Paddle Boards 114.13 and 116.13 respectively, to provide requiredEMI shielding. At the same time, the Metallic Outer Cable Braid 1302 isconnected to the txHPD and rxHPD signal terminals, to provide aconductive path for the HPD signal. As is well known, the HPD signal isa quasi-static signal whose purpose is to inform the sink and sourcedevices of their mutual connectedness through the cable. By connectingthe HPD signal through the cable braid, this purpose is fulfilledwithout the need for a separate signal wire in the cable. It should benoted that the technique of carrying an auxiliary signal on the cablebraid is not limited to just the HPD auxiliary signal. It is potentiallyvalid for any auxiliary signal.

FIG. 14 shows a detailed diagram of the Second 8-Coax HDMI Cable 102.13of FIG. 13B, including detailed diagrams of the Second 8-Coax InputPaddle Board 114.13, the Second 8-Coax Raw Cable 108.13, and the Second8-Coax Output Paddle Board 116.13.

The Second 8-Coax HDMI Cable 102.13 incorporates one split dual shieldedcable element 1308 comprising two coax lines (1308A and 1308B) and acoupling capacitor C5.

The Second 8-Coax HDMI Cable 102.13 incorporates in the Second 8-CoaxRaw Cable 108.13 and a corresponding coupling capacitor C5 mounted onthe Second 8-Coax Input Paddle Board 114.13.

The Second 8-Coax Raw Cable 108.13 further includes three dual shieldedcable elements, that is coax pairs 1310, 1312, and 1314,

The Second 8-Coax Input and Output Paddle Boards 114.13 and 116.13respectively are arranged to provide connectivity between the Input andOutput Connection Fields 212 and the Second 8-Coax Raw Cable 108.13. TheSecond 8-Coax Input Paddle Board 114.13 further includes paddingresistors R22 to R29, analogous to the padding resistors R1 to R8 ofFIG. 10, each padding resistor connected in series between a TMDS signalor clock terminal of the Input Connection Field 212 and one of the eightshielded conductors of the dual or split dual shielded cable elements.

The resistance value of each of the padding resistors R22 to R29 isdetermined as the difference between one half of the nominaldifferential impedance of the Second 8-Coax HDMI Cable 102.13, that is100 ohms for each of the high speed differential data signals, and theimpedance of each of the coaxial lines. For example, when 35-ohm coaxlines are used in the Second 8-Coax Raw Cable 108.13, each paddingresistor (R22 to R29) should have a resistance of 15 ohms, so that thenominal differential HDMI impedance of 100 ohms is present at the InputConnection Field 212.

The padding resistors R22 to R29 are omitted when 50-ohm coax lines areused. Alternatively (not shown in FIG. 14), shunt resistors analogous tothe shunt resistors R9 to R12 of FIG. 11 would be used where coax linesof a higher impedance than 50 ohms are used in the raw cable.

As shown in FIG. 13B, the TMDS HPD signal is carried over the MetallicOuter Cable Braid 1302. The Second 8-Coax Input Paddle Board 114.13includes an Electrostatic Discharge (ESD) resistor R30 of about 30 ohmsin series between the txHPD signal of the Input Connection Field 212 andthe Metallic Outer Cable Braid 1302. Similarly, the Second 8-Coax OutputPaddle Board 116.13 includes an ESD resistor R31 of about 30 ohms inseries between the Metallic Outer Cable Braid 1302 and the rxHPD signalof the Output Connection Field 214. The Second 8-Coax Input and OutputPaddle Boards 114.13 and 116.13 further comprise bypass capacitors C6and C7 respectively, each having a capacitance of about 1 nF, connectedbetween ground (txGnd and rxGnd respectively) and the HPD terminal(txHPD and rxHPD respectively). The purpose of the bypass capacitors C6and C7 is to dampen any ESD spikes that may occur when the Second 8-CoaxHDMI Cable 102.13 is plugged into the video equipment, in order toprotect its circuitry.

A preferred signal routing in the Second 8-Coax HDMI Cable 102.13 isillustrated in FIG. 14 and shown in Table 7 below. The differential TMDSData signals and the TMDS Clock signal are coupled through the paddingresistors R22 to R29 to the inner (shielded) conductors of the eightcoax lines.

The joined shields of the dual shielded cable elements 1310, 1312, and1314 are connected to carry respectively the HDMI signals SCL, SDA, andCEC.

The shields of the two coax lines 1308B and 1308A of the split dualshielded cable element 1308 are connected to carry respective two staticsignals namely: DDC/CEC Ground and +5V Power. Preferred signalassignments of the Second 8-Coax HDMI Cable 102.13 are shown FIG. 14 andin Table 7 below as examples, and different assignments may be equallyvalid.

TABLE 7 Preferred Signal Routing in Second 8-Coax HDMI Cable 102.13Boost Input Boost De- Output Connec- Raw De- vice Connec- HDMI tionCable vice Out- tion Signal Name 212 108.13 Input put 214 TMDS Data2Shield txD2s 1308A.shield --> --> rxD2s TMDS Data2+ txD2+ 1310.a D2+ C2+rxD2+ TMDS Data2− txD2− 1310.b D2− C2− rxD2− IMDS Data1 Shield txD1s1308A.shield --> --> rxD1s TMDS Data1+ txD1+ 1312.a D1+ C1+ rxD1+ TMDSData1− txD1− 1312.b D1− C1− rxD1− IMDS Data0 Shield txD0s 1308A.shield--> --> rxD0s TMDS Data0+ txD0+ 1314.a D0+ C0+ rxD0+ TMDS Data0− txD0−1314.b D0− C0− rxD0− TMDS Clock Shield txCKs 1308A.shield — — — Pgm -->rxCKs TMDS Clock+ txCK+ 1308.a D3+ C3+ rxCK+ TMDS Clock− txCK− 1308.bD3− C3− rxCK− DDC/CEC Ground txGnd 1308A.shield GND --> rxGnd CEC txCEC1314.shield --> --> rxCEC SCL txSCL 1310.shield --> --> rxSCL SDA txSDA1312.shield --> --> rxSDA Utility txUt n/c — — rxUt +5 V Power txPWR1308B.shield +5 V --> rxPWR Hot Plug Detect txHPD 1302(braid) --> -->rxHPD

Unboosted Cables

The techniques described above for carrying signals on the shields ofcoax lines or STP lines are also valuable when no boost device isintegrated in the cable.

While the Boosted Digital Video Cables 102.j include the Boost Device118 or the Modified Boost Device 118.12, which facilitate use of thesecables over greater distances, equivalent unboosted cables can providethe same facilities as the boosted cables but for use over shorterdistances, typically not exceeding 2.0 meters for AWG34 wire gauge, 2.5meters for AWG30 or 5 meters for AWG28 wire gauge depending on physicalproperties such as intrinsic impedance, capacitance etc.

FIG. 15 shows a configuration 1500 of a generic Unboosted Digital VideoCable 1502.k which may be any of a number of types described in thefollowing figures, according to embodiments of the invention,interconnecting the Video Source Device (Tx) 104 and the Video SinkDevice (Rx) 106. The generic Unboosted Digital Video Cable 1502.k issimilar in all respects to the generic Boosted Digital Video Cable102.j, j=k, with the difference being an Unboosted Output Paddle Board1504.k which replaces the Output Paddle Board 116.j of the genericBoosted Digital Video Cable 102.j.

Various embodiments of the Unboosted Digital Video Cables 1502.k of theinvention, described in more detail below, make use of the same InputPaddle Boards 114.j and the same Raw Cables 108.j, as correspondingboosted cables, including the inventive techniques described earlier, ofcarrying signals on the shields of dual shielded cable elements, i.e.coax pairs (FIGS. 3, 5, 7, 10, 11) or Shielded Twisted Pairs 302 to 310(FIGS. 4, 6, 8), or of split dual shielded cable elements as shown inFIG. 14 which also includes the concept of carrying a signal on theMetallic Outer Cable Braid 1302.

With the exception of the First 8-Coax HDMI Cable 102.12 which relies onthe single-ended to differential converter (SDC) 1216 in the ModifiedBoost Device 118.12, all previously described boosted digital videocables have an unboosted cable equivalent, as shown in Table 8 belowwhich lists for all described cable types reference numbers showingcorresponding boosted and unboosted cable versions. 102.10

TABLE 8 Boosted and Unboosted Digital Video Cable equivalents BoostedRaw Unboosted Unboosted Output Cable Type Cable Cable Cable Paddle BoardHDMI, coax 102.1 108.1 1502.1 1504.1 HDMI, STP 102.2 108.2 1502.2 1504.2HDMI + HEAC, coax 102.3 108.3 1502.3 1504.3 HDMI + HEAC, STP 102.4 108.41502.4 1504.4 DisplayPort, coax 102.5 108.5 1502.5 1504.5 DisplayPort,STP 102.6 108.6 1502.6 1504.6 Low-Z0 coax HDMI 102.10 108.1 1502.101504.10 High-Z0 coax HDMI 102.11 108.1 1502.11 1504.11 First 8-coax HDMI102.12 108.12 N/A N/A Second 8-coax HDMI 102.13 108.13 1502.13 1504.13

FIGS. 16 to 24 showing unboosted cable types are distinguished from theotherwise identical corresponding figures of boosted cable types, by newUnboosted Output Paddle Boards 1504.k, shown in bold outline in thedrawings. These Unboosted Output Paddle Boards 1504.k may be realized asidentical mirror images of the corresponding Input Paddle Boards 114.j,k=j.

FIG. 16 shows a Basic Unboosted Coax HDMI Cable 1502.1 based on coaxtechnology according to an embodiment of the invention, including theInput Connection Field 212, the first Input Paddle Board 114.1, thefirst Raw Cable 108.1, the Output Connection Field 214, as well as afirst Unboosted Output Paddle Board 1504.1.

FIG. 17 shows a Basic Unboosted STP HDMI Cable 1502.2 based on ShieldedTwisted Pair (STP) technology according to an embodiment of theinvention, including the Input Connection Field 212, the second InputPaddle Board 114.2, the second Raw Cable 108.2, the Output ConnectionField 214, as well as a second Unboosted Output Paddle Board 1504.2.

FIG. 18 shows an Unboosted HEAC-Capable Coax HDMI Cable 1502.3 based oncoax technology according to an embodiment of the invention, includingthe HEAC-capable Input Connection Field 412, the third Input PaddleBoard 114.3, the third Raw Cable 108.3, the HEAC-capable OutputConnection Field 414, as well as a third Unboosted Output Paddle Board1504.3.

FIG. 19 shows an Unboosted HEAC-Capable STP HDMI Cable 1502.4 based onShielded Twisted Pair (STP) technology according to an embodiment of theinvention, including the HEAC-capable Input Connection Field 212, thefourth Input Paddle Board 114.4, the fourth Raw Cable 108.4, theHEAC-capable Output Connection Field 214, as well as a fourth UnboostedOutput Paddle Board 1504.4.

FIG. 20 shows an Unboosted Coax DisplayPort Cable 1502.5 based on coaxtechnology according to an embodiment of the invention, including theDisplayPort Input Connection Field 612, the fifth Input Paddle Board114.5, the fifth Raw Cable 108.5, the DisplayPort Output ConnectionField 614, as well as a fifth Unboosted Output Paddle Board 1504.5.

FIG. 21 shows an Unboosted STP DisplayPort Cable 1502.6 based onShielded Twisted Pair (STP) technology according to an embodiment of theinvention, including the DisplayPort Input Connection Field 612, thesixth Input Paddle Board 114.6, the sixth Raw Cable 108.1, theDisplayPort Output Connection Field 614, as well as a sixth UnboostedOutput Paddle Board 1504.6.

FIG. 22 shows an Unboosted Low-Impedance Coax HDMI Cable 1502.10 whichis identical to the Basic Unboosted Coax HDMI Cable 1502.1 of FIG. 16except for the Low-Impedance Input Paddle Board 114.10 instead of thefirst Input Paddle Board 114.1, and includes the Input Connection Field212, the first Raw Cable 108.1, the Output Connection Field 214, as wellas a Low-Impedance Unboosted Output Paddle Board 1504.10.

The Low-Impedance Unboosted Output Paddle Board 1504.10 includes paddingresistors R32 to R39 which correspond to the padding resistors R1 to R8of the Low-Impedance Input Paddle Board 114.10 and in combination with alow-impedance raw cable provide the correct nominal cable impedance atthe cable connectors according to the HDMI specification.

FIG. 23 shows an Unboosted High-Impedance Coax HDMI Cable 1502.11 whichis identical to the Basic Unboosted Coax HDMI Cable 1502.1 of FIG. 16except for the High-Impedance Input Paddle Board 114.11 instead of thefirst Input Paddle Board 114.1, and includes the Input Connection Field212, the first Raw Cable 108.1, the Output Connection Field 214, as wellas a High-Impedance Unboosted Output Paddle Board 1504.11.

The High-Impedance Unboosted Output Paddle Board 1504.11 includes shuntresistors R40 to R43 which correspond to the shunt resistors R9 to R12of the High-Impedance Input Paddle Board 114.10 and in combination witha high-impedance raw cable provide the correct nominal cable impedanceat both cable connectors according to the HDMI specification.

FIG. 24 shows an Unboosted Low-Impedance 8-Coax HDMI Cable 1502.13,including the Input Connection Field 212, the Second 8-Coax Input PaddleBoard 114.13, the Second 8-Coax Raw Cable 108.13, the Output ConnectionField 214, as well as a Low-Impedance Unboosted Output Paddle Board1504.13.

The Low-Impedance Unboosted Output Paddle Board 1504.13 is similar tothe Second 8-Coax Output Paddle Board 116.13 of FIG. 14, but instead ofthe Boost Device 118 comprises padding resistors R44 to R51 analogous tothe padding resistors R22 to R29 of the Second 8-Coax Input Paddle Board114.13, each padding resistor connected in series between a TMDS highspeed data or clock terminal of the Output Connection Field 214 and oneof the eight shielded conductors of the dual or split dual shieldedcable elements of the Second 8-Coax Raw Cable 108.13.

The Low-Impedance Unboosted Output Paddle Board 1504.13 furtherincludes: an ESD resistor R52 an isolating capacitor C9; and a bypasscapacitor C10, these components corresponding to the ESD resistor R31,the isolating capacitor C4 and the bypass capacitor C7 of the Second8-Coax Output Paddle Board 116.13, for permitting the HDMI HPD signal tobe carried over the Metallic Outer Cable Braid 1302 of the Second 8-CoaxRaw Cable 108.13.

A large number of cable versions, boosted and unboosted, have beenbriefly described. Further combinations of the described features may bereadily devised, for example cables similar to the Second 8-Coax HDMICable 102.13 or the Unboosted Low-Impedance 8-Coax HDMI Cable 1502.13,but employing eight coax lines of the correct (50 ohms) impedance, thusavoiding padding resistors. The use of dual shielded cable elements anda split dual shielded cable element as well as the metallic cable braidpermits such a cable to carry to carry 14 HDMI connections. Anotherexample would be a cable of eight high-impedance coax lines, requiringshunt resistors for proper impedance matching when high-impedance coaxlines are employed. No padding or shunt resistors are needed when coaxlines of the nominal (50 ohms for HDMI) impedance are used.

Although various exemplary embodiments of the invention have beendisclosed, it should be apparent to those skilled in the art thatvarious changes and modifications can be made which will achieve some ofthe advantages of the invention without departing from the true scope ofthe invention.

For example, the following elements according to various exemplaryembodiments of the invention described above may be combined toadvantage in applications such as an HDMI cable with or without HEACcapability, a Display Port cable, or similar high speed data cables:boosting of differential signals; carrying an auxiliary signal includingpower and ground on the common shield of a dual shielded cable elementwhich may be a pair of coaxial lines or a shielded twisted pair;carrying auxiliary signals including power and ground on the individualshields of a split dual shielded cable element; carrying an auxiliarysignal including power and ground on the cable braid; using raw cableelements of lower or higher impedance than the impedance specified forthe cable, and correcting the impedance with a resistor network (seriesor shunt resistors respectively); carrying a differential high speedsignal through the cable, but retrieving only one polarity of the signalto be subsequently restored at the cable end in a single-ended todifferential converter.

A person understanding this invention may now conceive of alternativestructures and embodiments or variations of the above all of which areintended to fall within the scope of the invention as defined in theclaims that follow.

1. A cable for carrying a high speed differential digital data signalsand one or more auxiliary signals between a source device and a sinkdevice according to a cable specification, the cable comprising: a rawcable, comprising a split dual shielded cable element, comprising twoshielded conductors, each of said two shielded conductors being enclosedin an individual shield; individual shields of the shielded conductorsare designated for carrying respective auxiliary signals; and theshielded conductors of the split dual shielded cable element aredesignated for carrying the high speed differential digital data signal.2. The cable of claim 1, further comprising a coupling capacitor forcapacitively coupling the individual shields of the split dual shieldedcable element.
 3. The cable of claim 2, wherein capacitance of thecoupling capacitor is chosen to be low enough not to cause cross talkbetween low speed auxiliary signals, but high enough to preservetransmission characteristics of the dual shielded cable element withrespect of the high speed differential signal.
 4. The cable of claim 1,further comprising a boost device for boosting the high speeddifferential digital data signals.
 5. The cable of claim 1, the rawcable further comprising a dual shielded cable element, comprising twoshielded conductors and a common shield; wherein: the two shieldedconductors of the dual shielded cable elements are designated forcarrying a respective high speed differential digital data signal; andthe common shield of the shielded conductors is designated for carryingan additional auxiliary signals.
 6. The cable of claim 1, furthercomprising a first circuit carrier for connecting the raw cable to thesource device, and a second circuit carrier for connecting the raw cableto the sink device.
 7. The cable of claim 6, wherein the first circuitcarrier comprises: terminals for connecting the high speed differentialdigital data signal from the source device to respective shieldedconductors of the split dual shielded cable element; and terminals forconnecting respective auxiliary signals from the source device to theindividual shields respectively.
 8. The cable of claim 6, wherein thesecond circuit carrier comprises: terminals for connecting the highspeed differential digital data signals from respective shieldedconductors of the split dual shielded cable element to the sink device;and terminals for connecting respective auxiliary signals from theindividual shields to the sink device.
 9. The cable of claim 2, whereincapacitance of the coupling capacitor is about 1 nF.
 10. The cable ofclaim 1, wherein the cable specification is a High-Definition MultimediaInterface (HDMI) standard.
 11. The cable of claim 1, wherein theindividual shields of the split dual shielded cable element aredesignated for carrying Power and Ground auxiliary signals.
 12. Thecable of claim 1, wherein the individual shields of the split dualshielded cable element are designated for carrying a Hot Plug Detect(HPD) auxiliary signal and CEC (Consumer Electronics Control) auxiliarysignal.
 13. The cable of claim 5, wherein the raw cable comprises onlytwo split dual shielded cable elements, and two dual shielded cableelements, each dual shielded element comprising two shielded conductorsand a common shield.
 14. The cable of claim 1, wherein the cablespecification is a DisplayPort standard.
 15. The cable of claim 1,wherein said split dual shielded cable element is a split dual coaxialelement, comprising two coaxial lines whose shields are capacitivelycoupled to one another, and each coaxial line enclosing one shieldedconductor.
 16. The cable of claim 5, wherein the dual shielded cableelement is a dual coaxial element, comprising two coaxial lines whoseshields are joined, and said shields of each coaxial line enclosing arespective shielded conductor.
 17. A method for transmitting a highspeed differential digital data signal and one or more auxiliary signalsbetween a source device and a sink device according to a cablespecification over a cable extending between the source device and thesink device, the method comprising: carrying the high speed differentialdigital data signal over the cable in two shielded conductors of a splitshielded cable element, each of the two shielded conductors having anindividual shield; and carrying said one or more auxiliary signals onrespective individual shields of the shielded conductors.
 18. The methodof claim 17, further comprising capacitively coupling the individualshields of the split dual shielded cable element.
 19. The method ofclaim 17, further comprising carrying yet another auxiliary signal on acommon shield of a dual shielded cable element comprising two shieldedconductors and the common shield.
 20. The method of claim 17, whereinthe carrying is performed according to the cable specification, which isa High Definition Multimedia Interface (HDMI) standard or a DisplayPortstandard.